A Brief Guide to Selecting the Proper Lightbulb

Do you need to buy a new lightbulb? Don’t stand and scratch your head in the aisle at your hardware store! This blog has some valuable tips for how to select the proper lightbulb just by looking at the information printed on the box.


Lightbulb technology has changed tremendously over the last two decades. For many years, every lightbulb was essentially a small variation of the tungsten filament incandescent lightbulb that had been commonplace pretty much since the lightbulb was invented. Modern technology radically changed all of that. Today, compact fluorescent lightbulbs and LED lightbulbs are by far the most common types of bulbs you will see on store shelves (with a few occasional exceptions for things like outdoor lighting and display lights).

Don’t be worried if you have an older light fixture—modern bulbs are designed to work in the same standard lightbulb sockets we have relied upon for pretty much as long as electric lighting has existed. The only difference is that these modern bulbs use far less electricity and often give you increased flexibility for everything from light temperature to dimmability. We recommend you try out a few different types of bulbs for yourself and find one that you like. Keep in mind that not all types of bulbs are ideal for every situation, either, so the average home will typically use a mixture of different bulb technology for different applications.


This is where things start to get tricky when purchasing a lightbulb. Bulbs come in a big variety of different shapes, sizes, and styles for different applications. For example, chandeliers will typically use a sort of decorative bulb that is designed to blend into the fixture with a flame-like shape, an elongated oval, or some other creative form. Meanwhile, your standard table or floor lamp will use the same old lightbulb shape that has been used in lights for decades.

Recessed lighting is a whole different thing entirely. For years, recessed lights (or “can lights” as they are sometimes referred to) used a special shape that projected all of its light downward into the room it’s illuminating. Many of these fixtures still do use these bulbs, and they likely aren’t going anywhere anytime soon. However, modern fixtures actually include the bulb as one standalone piece that press-fits into your lighting can. These are generally more expensive, but they offer you more design creativity, bonus features, and an extremely long lifespan that often carries a warranty for five years or more.

If you do need to replace a specialty bulb, we strongly recommend bringing the burned-out bulb to your hardware store or electrical supply and comparing it directly to a replacement. Buying a bulb that is too large means the bulb won’t fit, while a bulb that is too small won’t project enough light into your space, even if the brightness measurements are correct.


Watts used to be the defining way to measure the brightness of a lightbulb because all bulbs were essentially identical. They all used the same material as a filament (with maybe a few incredibly small differences), and that same material would emit the same amount of light when you passed a particular amount of energy through it. Therefore, even though wattage is a measure of electrical energy, it still became a pretty reliable way of defining how bright a lightbulb might be.

Wattage is a simple term to define the exact amount of electrical energy passing through something, as defined by the mathematical formula “Watts = volts (x) amps.” Let’s look at a practical example. With a standard lightbulb, we know that the voltage running through the bulb will be 120 volts (the North American standard voltage). Therefore, by controlling the number of amps (or electrical current) flowing through the bulb, we can increase or decrease the brightness of a bulb. Therefore, the higher the wattage of a bulb, the brighter it was (and the more energy that brighter bulb would consume).

Today, watts are pretty much outdated as a measure of lightbulb brightness because modern LED, fluorescent, and other types of lightbulbs use significantly fewer watts to produce the same amount of light that older incandescent bulbs did. This is why instead of seeing bulbs that range between 25 and 100+ watts on store shelves, you’re seeing bulbs that use around 15 watts or less. However, many manufacturers have tried to simplify the purchasing process by printing a “wattage equivalent” on the box. This is essentially to make it easier for consumers who know roughly how bright of a light they want based on the old wattage measurement. By buying a bulb with a similar wattage equivalent, they’re getting a bulb that emits a similar amount of light to an incandescent bulb of that indicated wattage.


One of the measurements you will see on a box of lightbulbs is a number indicated in a measurement called “lumens.” A lumen is a unit used to measure emitted amount of light from a particular light source. The actual definition is a bit confusing, but an easy way to think about it is that a single candle produces 12.57 lumens because the area of a sphere is 12.57 times the radius of that sphere. Generally, the more lumens a lightbulb produces, the more light that bulb emits over a wide area.

However, there is an exception to this—bulbs that are designed to specifically direct their light over a narrower area will have a lower lumen rating purely because they don’t emit that light in every direction. Therefore, be aware that a bulb designed for spot lighting may have a lower lumen rating than an omnidirectional bulb while still appearing to be much brighter. Don’t let that deceive you into buying the wrong type of bulb for your application.

Need help with a light fixture? Looking for assistance installing recessed lighting, a chandelier, or any other type of fixture? Get help from the experienced electricians at Lightning Bug Electric by dialing (404) 471-3847 today.